LOS ANGELES — I fear I won’t survive. My vision is blurred. I’m being chased by a pistol-packing militia member across the rooftops of an abandoned neighborhood. He’s already shot me. One more shot and I might be dead. Then I hear: “Your Titan is ready to drop. Signal when ready.” I point to a nearby parking lot below me and — boom! — a Transformers-like robot descends from the sky.

Leaping from the building’s roof, I slide into my mechanized beast’s chest and quickly assume the controls, swinging the 24-foot-tall walking tank around to my pursuer and blasting him to smithereens. That’s just one breakneck moment among the dozens I’ve experienced while playing the frenetic “Titanfall” (Electronic Arts, for the Xbox One, PC, $59.99).

“Titanfall” is the ambitious inaugural game from Respawn Entertainment, a studio that includes developers who worked on the landmark “Call of Duty: Modern Warfare” series. It’s clear after spending a few days clashing with Titans that they’ve changed the game again, refreshing the static shoot-’em-up genre with this fabulously fluid sci-fi shooter.

Any notion of interactive storytelling has been ejected into space in favor of a strictly online-only affair where each matchup between the game’s warring Frontier Militia and the Interstellar Manufacturing Corp. is comprised of real players portraying balletic gun-toting pilots. They’re each equipped with jet packs and can call on those behemoth Titans for support.

Pilots begin most matches without a Titan sidekick. They can speed up its construction occurring in a ship overhead by shooting down foes and completing objectives in the game’s five multiplayer modes — from the death match-like “Attrition” to the rock-’em-sock-’em “Last Titan Standing” — that are spread across 15 of the most vertical levels ever depicted in a shooter.

The expansive battlefields aren’t merely populated with other human pilots. There are also dozens of computer-controlled foot soldiers whose presence imbues “Titanfall” with the feeling of an epic war. Enemies serve as fodder. Their deaths shave off time until the next Titan is ready, while allies helpfully lead pilots to the next closest kerfuffle on the map.

It might all seem complicated. It’s not. There are so many different ways to play as either a free-running pilot on the ground or inside a lumbering Titan that it’s always entertaining, no matter if you’re a shooter newbie or hardcore “Halo” and “Call of Duty” devotee. Heck, even losing is fun because the missions end with an adrenaline-pumping race to an escape vessel.

An unfulfilling but necessary campaign mode attempts to make sense of the man-versus-machine conflict that’s waging between the militia and the IMC. It’s inadequate because it provides zero background on how or why these factions are at each other’s steel throats, but it’s paramount because playing completely through the mode unlocks two of the game’s three Titans.

No, “Titanfall” isn’t “2001: A Space Odyssey.” It’s Space Mountain. By relinquishing a true plot and instead masterfully blending guns, robots, parkour and sci-fi cliches into a giant interactive thrill ride, Respawn Entertainment has put together an innovative toy box where players can act out their own stories on otherworldly front lines.